Machinery for making welded pipe



Sept. 20, 1932 CAMMEN 1,373,376.

MACHINERY FOR mum wswan Pm Filed Feb. 4. 1931 O l s "3 w r m w INVENTOR.a 1%, @0140 Patented Sept. 20, 1 932 PATENT- OFFICE- LEON CAMMEN, OF NEWYORK, N. Y.

MACHINERY FOR MAKING WELDED II IE Application filed February 4, 1931.Serial No. 513,337.

The present invention relates to apparatus for making spiral pipe from astri of sheet material. Spiral pipe is made by orming a strip of sheetmetal into a helix and securing the meeting edges of successive turns ofthe helix as, for example, by welding.

The present invention has for an object to provide an improved method ofand means for forming a strip of metal into a helix to make a pipetherefrom.

Another object is to provide an improved method and means for holdingthe successive turns of the helix in close engagement while uniting thesame.

Another object is to provide unimproved method of and means forprogressively contacting the meeting edges of successive turns withsubstantial pressure and welding them at the point of pressure.

Another object is to provide an improved arrangement for bending thesheet metal between bendin rolls.

Another ob ect is to provide means for first bending the sheet metal to'form ahelix of 2.3 a size approximating that required for the finalform of the pipe and thereafter further bending the-sheet metal to finalform.

Another object is to provide an improved drive for rotating the pipe asformed.

The nature" and objects of the invention will be better understood froma description of an illustrative embodiment thereof and for the purposeof which description reference is made to the accompanying drawingforming a part hereof and in which Figure 1 is a somewhat diagrammaticsectional view showing a Selected embodiment of the invention;

Fig; 2 shows a view of the skelp, partly welded and artly unwelded, endview as seen by looking from the right to the left hand side of Fig. 1.

Fig. 3 shows, in vertical section, a view of one of the constructionsfor turning the pige.

ig. 4 shows, diagrammatically, the cycle of operationof the deviceshown'in Fig. 1.

The present invention refers, particularly to the type of machinery formaking spirally 9 welded pipe wherein the skelp is passed betweenbending rolls, usually three, of which the one on the inside is shown at1, while the outside rolls are not shown. 7 By properly setting thetwist rolls (not shown) the edges of the seam, such as 27 and 28, shownhere widely apart, may be brought together as closely as desired, evento the extent of overlapping, but it is impossible to produce a pressurein the seam just by the action of the twist and bending rolls. Inanother apo plication (Ser. No. 496,212) I have shown that to producesuch a pressure it is necessary, first, to provide a guide, such as 8,bearing against the edge of the seam, such as 28; next, to produce by anapplication of power 5 a motion of rolling andadvancing in the weldedpart of the pipe within reasonable distance from the guide 8, and,finally, provide such an arrangement of parts that the diameter of thecylinder of skelp between the 7 forming rolls and the locus of weldingis different from that of the welded part of the pipe.

The present invention deals with improved means to producesimultaneously the forward and turning motion of the welded part of thepipe, and to satisfy the following conditions in doing it: (1) Make itpossible to apply enough force to cause -a pressure of the desiredmagnitude in the seam at the place of welding; (2) make the deviceeffective even where the pipe is very smooth; (3) provide a device ofsuch a type that it would be applb cable to a large range of sizes ofpipe without material changes every time and large loss of time due tosuch changes. The motion of the welded part of the pipe will naturallyinduce a similar motion in the unwelded butcoiled part.

In Fig. 1, 1 is the end of the shaft of the 00 inside bending roll, withskelp 29 around it. It will be noted that the skelp at the bottom is inclose contact with roll 1, or rather sleeve 31 thereof, but at the topof the skelp is quite far away from the roll. This is the naturalcondition in making spiral pipe. 2 is a stationary mandrel,substantially of the same diameter as the coiled skelp, and therefore ofa diameter larger than that of roll 1.

Among other things it may carry guide 8.

Usually it will not be concentric with roll 1. Rolls 3 and 4 are shownin two pieces, 3 being much longer than 4; this is however merely apreferred design. These rolls are held on shaft 32 by means of a collar33. These rolls line of mandrel 2 when extended coincides with agenerating line of rolls 3 and 4. It is preferable that this commongenerating line should pass through or in the immediate proximity ofguide 8, as shown in Fig. 1. A spacing between rolls 3 and 4 isprovided, and that is, i. e. at 20, where the weldin takes place, thewelding current being supp ied by discs 10 and 11.

Because of the fact that roll 3 is of smaller diameter than mandrel 2,the skelp 29 follows for a while, until say 29-a, the outline of mandrel2 but, if twisted with enough power thereafter, tends to approach thediameter of rolls 3 and 4, and when this has been accomplished, followsthe outline of 39. This is shown in Fig. 2. In order to produce thiseffect, two things are necessary, first, a twist exerted on the skelplocated to the right of 20, and second, resistance to either the twistor forward motion of the part of the skelp located to the left of 20.The method to produce the former will be described hereafter; theresistance to this twist is in part produced by the presence of guide 8,and may be increased to any desired extent by applying some kind of abrake on the skelp to the left of 20. This latte. is not shown here.

The coiled skelp 29 is coming from the bending roll 1 and is passingover the mandrel 2 so as to bring guide 8 within the open seam 27-28;thereafter the skelp goes on to rolls 3"and 4 and is then subjected tothe action of rope 12. This rope (Fig. 1) passes over the skelp makingseveral turns about the welded part of the pipe (snubbing it), and issubjected at one end (42, Fig. 3) to an upward pull, of an intermittentnature, and at the other end to the action of weight 13 (or some otheropposing force, e. g. spring). As the rope end at 42 is being ulledupwards, the pipe tends to turn in the direction of the arrow, Fig. 3,and at the same time, because of the presence of guide 8 in the openseam. the pipe has to move forward,

i. e. to the right in Fig. 1.

If the rope ends 13 and 42 were connected into an endless rope, and theweight replaced by a pulley under tension, e. g. an idler pulley, theeffect would have been exactly the same as is obtained with thearrangement of rope shown in Fig. 3, and the drive would have been acombination of the well-known rope drive and forward propulsion by meansof guide 8, neither of which is new and the combination is notsufficiently novel to be worth claiming even if it did work as requiredhere, which it does not.

The reason why a combination of an endless rope drive or its equivalentwith a guide pin such as 8 will not work is that it calls for twonon-compatible actions to be performed simultaneously. Assume that we dohave an endless rope drive: obviously, in order to move to the right inFig. 1, either the rope 12 must slide on the pipe, or the pipe mustcarry the rope with it. But the rope cannot both slide on the pipe anddrive the pipe by friction as the two things are not compatible: if thecoeflicient of friction is so low that the rope slides on the pipe, itwill not turn the pipe with suflicient force, and if the friction issuch that the rope will turn the pipe against the various resistances,it will not slide on the pipe. Also obviously the pipe cannot carry therope with it if the rope be an endless one and therefore ofpredetermined length. No endless rope drive or its quivalent willtherefore work.

To meet these peculiar requirements the novel drive set forth here hasbeen invented. In this drive (Fig. 3) the rope is given a reciprocatingmotion as by eccentric 44'which alternately pulls beam 43 up and thenlets it come down. When beam 43 goes up it pulls up rope 42 attached toit and in doing so snubs the rope about the pi e and causes the latterto turn in the directlon of the arrow, as well as to move forward, i. e.to the right in Fig. 1, under the influence of guide 8, the rope beingcarried with the ipe to the right. This might cause trouble if the raiseat 42 were such as to cause the pipe to make a full turn or more, but ifit is such as to cause the pipe to turn through a small angle only (sayunder 180 deg., and preferable not more than deg.) the amount to whichthe r0 is carried with the pipe will not be su cient to cause trouble.On the downward stroke of the eccentric the rope unwinds itself underthe action of the weight which is not sufficient even to keep the ropetaut and the rope takes the original position except that it has beencarried for a certain distance to the right with the pipe. There ishowever provided a wiper 46 is stationary and may be in the form of aring or finger a ut the pipe and it does not (permit the rope to move tothe right beyon a certain point. Not only that but if the pipe is movedto the right by some other means, it tends to sweep the ro e 12 to theleft which it can do because at t at time the rope is not being pulledupwards by beam times there will be either one or two ropes loose and ina condition to be pushed back by them respective fingers (46, 47 or 50),whileat least one rope will be turning the pipe and moving it to theright.

Any engineer can devise a number of methods of driving the rope 12 toobtain the intermittent motion indicated here, as by eccentrics, cams,Geneva motions, etc. The horizontal beam 43 can be replaced by avertical lever with a reciprocating motion, etc. The drive simplyrequires a series of coordinated short jerks following so closely uponeach other as to provide what in practice amounts to a continuous drive,the driving element aftereach jerk being released and means beingprovided to assist it in returning to its original position with respectto the pipe structure.

It should be clearly borne in mind that the part of the pipe to whichthe rope drive is applied has already been welded, or that some othermeans is provided to convert it into a rigid structure. To understandthe necessity of this, let us assume that roll 4 has been extended untilit comes under ropes 12, 48 and 49, and that the pipe is not welded. Theaction of the rope will then wind the skelp tight around roll 4 and makeit impossible for the skelp to move forward. On the other hand, if weinsert into the skelp, between say 45 and 50, a loose cylinder of anexternal diameter equal say to the desired diameter of the pipe(internal), the rope will coil up about it and carry it with it. Abetter plan is however to have a piece of the skelp, say from 20 to 50,or roughlfitwo turns, welded first by some means, as e. g. hand welding.It is true of course that this iece may have to be thrown out later, butthls does not amount to much in a very long coil of skelp, particularlyif the end of the first coil of skelp s welded to the beginning of thenext one, as 1s common practice today.

As roll 4 does not have to support the pipe against the pull of theropes, it can be made rather short, in fact just long enough to supportthe action of the welding disc 11. Either roll 3 or roll 4 may beinsulated from each other, as by asbestos sleeve 51 and end washers 52.As the welding current is of very low voltage, the roblem of insulationis here quite simple. n the other hand, the rope drive may exert apowerful upward or downward pull, and if not properly taken care of,might produce a distortion in the pipe. To prevent this, bearings 53and" 54 are provided. These bearings have to be of such a character asto permit free turning of the pipe and also its free motion to theright. To indicate this character of the bearings, they have beendiagrammatically shown as casters. Depending on the size of the pipe,one, two or more sets may be needed.

While for the sake of clarity of description the driving elementdescribed here has been referred to, and shown in Fig. 3, as a rope,

Under certain conditions, e. g. where the.

surface of the skelp is not too smooth, a chain can be used instead of arope. Finally, a magnet or magnets may be used to produce the equivalentof the frictional effect of the Another obvious substitution rope, andare therefore comprised under that term.

In the illustration, Fig. 1, the guide 8 is shown as part of mandrel 2which is a convenient but not essentially necessary construction. Theguide 8 has to be located within the seam 27 28, but it does not matterat all how it is supported, and e. g. itmight be suspended from somestructure above the pipe. In Fig. l the guide and welding rolls lO'and11 are shown at the top of the pipe. This seems to be the best locationfor these parts, largely because it permits to observe conveniently theaction of the welding mechanism, but there is no basic reason why theseparts should not be placed elsewhere.

While resistance welding has been referred to here, the apparatus setforth in this specification canbe applied to all forms of welding wherea pressure in the seam is desired.

As shown in the drawing, Fig. 1, mandrel 2 is supported by an extensionof shaft 1 which also carries the inside bending roll 31. The mandrelcan be however executed as an integral part of shaft 9, or, indeed, maybe omitted entirely, though at some sacrifice in convenlence.

As shown in Fig. 1, roll 4 extends only for a short distance from 20. Ifdesired, it can extend as far as 45, and if it extends further, willcause binding. It would be possible of course to reduce its diameterslightly and then extend it as far as desired to the right, but the partbeyond 45 cannot be the active part of the roll.

I claim:

1. A machine for forming sheet metal pipe comprising a mandrel, meansfor bending a metal strip to the form of a helix about said mandrel, aroll in substantial alignment w1th said mandrel but eccentric theretoand means for formin said helix about said roll.

2. A mac ine for forming sheet metal pipe comprising a mandrel of adiameter larger than that of the pipe to be formed, means for forming ahelix of sheet metal and passing the same over the mandrel, aligned andspaced rolls of smaller diameter than the mandrel and means forre-formin the helix to substantially the diameter 0 a said aligned rollson said rolls and means for welding the joint of the helix at the pointwhere the joint passes between the aligned rolls, said rolls beingelectrically insulated from each other. 5 3. A machine for forming sheetmetal pipe comprising a mandrel and two aligned spaced rolls ineccentric alignment with said mandrel and means for coiling a sheetmetal strip first on said mandrel and then on said rolls.

4. A machine for forming spiral pipe comprising in combination formingrolls for bending a strip to the form of helix, a mandrel ofsubstantially the diameter of the helix and over which the helix passesfrom the forming rolls, aguide associated with said mandrel andengageable with the helix to resist longitudinal movement thereof andmeans for bending said strip to a smaller radius as the helix passesfrom the mandrel to form a continuous pipe.

5. A machine for forming spiral pipe comprising in combination formingrolls for ending a strip to the form of a helix, a mandrel ofsubstantially the diameter of the helix and over which the helix passesfrom the forming rolls, means associated with said mandrel andengageable with the helix to resist movement thereof longitudinally. ofthe mandrel, a roll of smaller diameter than the mandrel in alignmentwith said mandrel, one element of the roll being in alignment with anelement of the mandrel, means for bending the helix to the diameter ofthe roll, and means for securing the adjacent edges of the helix to forma pipe.

6. A machine for formin spiral pipe comprising, in combination, formingrolls for bending a strip to the form of a helix, a

4 mandrel of substantially the diameter of the helix and over which thehelix passes from the forming rolls, means associated with said mandreland engageable with the helix to resist movement thereof longitudinallyof the mandrel, a member of smaller diameter than the mandrel projectingtherefrom and having its surface in one position forming substantially acontinuation of the surface of the mandrel, means for bending the helixto a smaller diameter about said member as it passes from the mandrel,and means for securing together the edges of the helix.

7. machine for forming spiral pipe comprising, in combination, a mandrelof a diameter greater than that of the pipe to be formed, means forbending a strip to the form of a helix and for feeding said stripforward over the mandrel, a cylindrical member of smaller diameter thanthe mandrel projecting in substantial alignment with said mandrel in thedirection of movement of the. helix and having one element of itssurface in alignment with an element of the mandrel, means for bendingthe helix to a smaller diameter about said cylindrical member as thehelix passes from the mandrel over said cylindrical member, and meansfor securing together the edges of the helix.

8. A machine for forming spiral pipe comprising, in combination, amandrel of a diameter greater than that of the pipe to be formed, meansfor bending a strip to the form of a. helix and for feeding said stripforward over the mandrel, a cylindrical member of smaller diameter thanthe mandrel projcctin in substantial ali nment with said man rel in thedirection 0 movement of the helix and having one element of its surfacein alignment with an element of the mandrel, means for rotating the pipebeing formed about said 0 lindrical member at a velocity sufficientlyhigh relative to the velocity of the helix to draw said helix to asmaller diameter about the cylindrical member and to close the jointbetween successive turns with substantial pressure and means forpermanently securing the joint.

Signed in New York, in the county and State of New York, this 2nd day ofFebruary, 1931.

LEON CAMMEN.

